1. Technical Field
The present invention relates to a technique for correcting the unsteadiness or shaking of a moving image filmed by hand through a portable video camera or the like.
2. Description of the Related Art
A hand shake correction function for correcting hand shake in a filming device such as a portable digital video camera or a digital camera with a moving image filming function is known. In addition to importing frames at a prescribed sampling rate, this type of filming device, clips images of a display subject area of a fixed area from each frame and sequentially displays them. When the filming device corrects the hand shake, it calculates, for every frame, a direction and a size of a shake of an image caused by the hand shake as a hand shake amount, and relatively moves the display subject area within the frame based on the hand shake amount, so that the display subject area is fixed regardless of the hand shake. As a result, as the filming device constantly clips the images of the constantly positioned display subject area from each frame, by sequentially displaying the images, a moving image display with no hand shake is realized (see, for example, JP-A-1-125064).
Also, in a camera which films a motionless image, a shake reduction camera which has a shake detector such as, for example, an acceleration sensor, and reduces a reduction in image quality due to a distortion of images using detected shake information, has been known. In this type of shake reduction camera, one has been known which, by predicting the shake based on the shake information and starting an exposure at a time when the shake decreases, enables capturing an image with no shake (see, for example, JP-A-8-320511). Consequently, at a time of a moving image reproduction display, a moving image display with no shake is also enabled by predicting the shake of the frames, and selecting and displaying only frames in which the shake decreases.
However, there is a problem in that, at the time of the moving image reproduction display, it is necessary to carry out a hand shake amount calculation process, a display subject area movement process and a display subject area extraction process, or a shake prediction process, for every frame. Consequently, in the event that the frame sampling rate when filming is high, it is necessary for the filming device to include a sophisticated and high-speed processor in order to carry but all of the processes for every frame at the time of the moving image reproduction display, the cost of the device increases.